lkml.org 
[lkml]   [2008]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [bug, 2.6.26-rc4/rc5] sporadic bootup crashes in blk_lookup_devt()/prepare_namespace()
    On 6/9/08, Cornelia Huck <cornelia.huck@de.ibm.com> wrote:
    > On Mon, 9 Jun 2008 16:28:09 +0200,
    >
    > "Vegard Nossum" <vegard.nossum@gmail.com> wrote:
    > > Everywhere else where we traverse the struct class->devices list, they
    > > have down(&class->sem); first and up(&class->sem); afterwards.
    > >
    > > Commit fd04897bb20be29d60f7e426a053545aebeaa61a even has this hunk:
    > > @@ -177,8 +177,7 @@ struct class {
    > > struct list_head devices;
    > > struct list_head interfaces;
    > > struct kset class_dirs;
    > > - struct semaphore sem; /* locks both the children and interface
    > > -
    > > + struct semaphore sem; /* locks children, devices, interfaces */
    > > struct class_attribute * class_attrs;
    > > struct class_device_attribute * class_dev_attrs;
    > > struct device_attribute * dev_attrs;
    > >
    > >
    > > So why doesn't block/genhd.c do this too? It seems to me that the
    > > mutex locking here is simply a remnant of old code that happened to
    > > not crash in most cases by chance.
    > >
    >
    >
    > Does this crash happen with the conversion to the class iterator
    > functions (should be in linux-next) as well? They take the class
    > mutex...

    Ah, you mean this:

    commit bb7ee70edb8745021c17ab604f2f4c897004e1c5
    Author: Greg Kroah-Hartman <gregkh@suse.de>
    Date: Thu May 22 17:21:08 2008 -0400

    block: make blk_lookup_devt use the class iterator function

    Use the proper class iterator function instead of mucking around in the
    internals of the class structures.

    Cc: Kay Sievers <kay.sievers@vrfy.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    So it should already be fixed, then. But I guess we'll have to wait
    for Ingo to run another couple of thousand tests to know the answer
    ;-)

    Thanks!

    Hm. Bugs already fixed elsewhere seems to be a recurring theme... I'll
    look harder for changes/fixes in other trees the next time :-(


    Vegard

    PS: But what about printk_all_partitions()? There are more than just
    this instance of the device list traversal code that don't use the
    class semaphore.

    PPS: Was that patch ever posted to LKML? I couldn't seem to find it.

    --
    "The animistic metaphor of the bug that maliciously sneaked in while
    the programmer was not looking is intellectually dishonest as it
    disguises that the error is the programmer's own creation."
    -- E. W. Dijkstra, EWD1036


    \
     
     \ /
      Last update: 2008-06-09 17:11    [W:2.753 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site